1. Field of the Invention
The present invention relates to a positioning device for positioning an area of a living body to be measured relative to a detecting probe during a measurement of a biological information with the use of an optical biological information measuring apparatus comprising the detecting probe and, more particularly, to the positioning device utilized in the apparatus to ensure an accurate and exact positioning of the area to be measured relative to the detecting probe.
2. Description of the Prior Art
An optical biological information measuring apparatus for measuring a biological information (which information is hereinafter referred to as a "biodata") from an area of a living body, for example, from a portion of the palm of a hand of a human being, has been well known in the art and is disclosed in, for example, the Japanese Laid-open Patent Publication No. 6-14906. This optical biodata measuring apparatus comprises a detecting probe for irradiating the area of the living body and also for receiving rays of light transmitted through and/or reflected from the area of the living body, and an optical measuring system for measuring or analyzing spectra of the transmitted and/or reflected light to provide the biodata of interest based on those spectra. When this optical biodata measuring apparatus is utilized to measure the biodata, conditions under which the biodata measurement is carried out are required to be kept uniform and consistent throughout the cycle of biodata measurement. So far as the inventors of the present invention have studied, if a portion of the palm of a hand is used as an area to be measured during measurement of the glucose content with the use of the optical biodata measuring apparatus, 1 mm displacement of the area to be measured relative to the detecting probe is suspected to result in variation of the measured glucose content in a quantity equal to or higher than 15 mg/dl.
In view of the above, when the prior art optical biodata measuring apparatus is utilized, the area to be measured is fixedly held in contact with the detecting probe by the use of, for example, a clip or double-sided adhesive tape.
However, the use of the clip or the double-sided adhesive tape to fixedly position the area to be measured relative to the detecting probe has the following problem. Specifically, the biodata measurement is cyclically performed while the detecting probe and the area to be measured are fixed in position relative to each other, the positional relationship between the detecting probe and the area to be measured can be kept constant throughout the repeated biodata measurement However, if the detecting probe once coupled the area to be measured is, after having been once removed, again coupled to the area to be measured during the biodata measurement (i.e., the detecting probe is repeatedly removed and fitted), it has been extremely difficult to align or fix the same area to be measured with the detecting probe. For this reason, with the prior art optical biodata measuring apparatus, variation in measured biodata tends to occur where the biodata measurement is carried out while the detecting probe is frequently removed and fitted to the area being measured.
In view of the above, the optical biodata measuring apparatus has been suggested in, for example, the Japanese Laid-open Patent Publication No. 8-332181, in which a template engageable or alignable with a particular area of the living body to be measured is prepared prior to the biodata measurement and is used during the biodata measurement to accommodate the area to be measured to thereby fix the area to be measured in position relative to the detecting probe while the latter has been arranged in the resultant template. However, this known optical biodata measuring apparatus has the following problem. Specifically, while the positional relation between the detecting probe and the area to be measured can effectively be fixed relative to each other even though the detecting probe is repeatedly removed from and fitted to the area to be measured, the template must be prepared having a shape and/or size complemental to that of the area to be measured for each of living bodies and, therefore, not only is preparation of the template for each living body complicated and time-consuming, but also a substantial amount of time tends to be spent before the biodata measurement starts.